1. Field of the Invention
The present invention relates to a waveguide filter with integral switching capability. Specifically, the present invention provides for a waveguide filter/switch with high power handling capability, hot switching and fast switching speed while maintaining optimum RF performance.
2. Description of the Prior Art
In general, prior art waveguide filters with integral switching capabilities have fallen into two types. One type uses an integration of discrete coaxial and/or waveguide switches and filters using RF cables and connectors which may or may not include quick disconnect techniques so that various elements of the switches and filters may be added or removed. The disadvantages of such devices are as follows. If coaxial components are used, these provide for poor power handling capability, negligible hot switching capability and poor RF performance. If waveguide components are used, these provide for slow switching time, limited hot switching capability, degraded RF performance and a large envelope size.
The other type of prior art device incorporates the use of resonators coupled to a coaxial or waveguide line to provide for filtering capability and with the use of diodes located across the resonators to provide for switching capability. The use of the switching diodes, however, provides a number of disadvantages. Specifically, the diodes cannot handle high power and the location of the diodes across the resonators does affect and degrade the performance of the filtering produced by the resonator itself. Specifically, the diode broadens out the bandpass or bandstop provided by the resonator.
Other types of prior art devices use other types of tuning or detuning members to effect the performance of the resonator, but do not provide for the desired high power handling capability, hot switching and fast switching. In addition to the above, reed switches have been used across the tuning resonator, but again such reed switches cannot provide for the desired high power handling capability with minimum degradation of the operation of the resonator.
References is made to the following prior art patents which disclose, some of the above described techniques. Karp U.S. Pat. No. 4,066,988; Wehner U.S. Pat. No. 3,521,199; Funck et al U.S. Pat. No. 4,642,584; Peppiatt U.S. Pat. No. 3,546,633; and Kouroda et al U.S. Pat. No. 3,569,874.